Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to ambient pressure in which operated. A moving galvanometer or oscillator reflects a laser beam to create scan lines of a latent image in opposite directions. A damping of the motion occurs per air density implicated by temperature and pressure, where the pressure changes occurring especially from altitude changes. During use, a drive signal, such as a pulse train, moves the galvanometer or oscillator at or near its resonant frequency. Based on a parameter of the drive signal, such as pulse width, the ambient pressure can be made known. In general, a high-pressure environment requires a relatively longer pulse width to resonate the galvanometer or oscillator in comparison to a shorter pulse width for a low-pressure environment. Corrections to print quality stem from the determined ambient pressure.

Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to ambient pressure in which operated. A moving galvanometer or oscillator reflects a laser beam to create scan lines of a latent image in opposite directions. A damping of the motion occurs per air density implicated by temperature and pressure, where the pressure changes occurring especially from altitude changes. During use, a drive signal, such as a pulse train, moves the galvanometer or oscillator at or near its resonant frequency. Based on a parameter of the drive signal, such as pulse width, the ambient pressure can be made known. In general, a high-pressure environment requires a relatively longer pulse width to resonate the galvanometer or oscillator in comparison to a shorter pulse width for a low-pressure environment. Corrections to print quality stem from the determined ambient pressure.

Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to ambient pressure in which operated. A moving galvanometer or oscillator reflects a laser beam to create scan lines of a latent image in opposite directions. A damping of the motion occurs per air density implicated by temperature and pressure, where the pressure changes occurring especially from altitude changes. During use, a drive signal, such as a pulse train, moves the galvanometer or oscillator at or near its resonant frequency. Based on a parameter of the drive signal, such as pulse width, the ambient pressure can be made known. In general, a high-pressure environment requires a relatively longer pulse width to resonate the galvanometer or oscillator in comparison to a shorter pulse width for a low-pressure environment. Corrections to print quality stem from the determined ambient pressure.

Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to ambient pressure in which operated. A moving galvanometer or oscillator reflects a laser beam to create scan lines of a latent image in opposite directions. A damping of the motion occurs per air density implicated by temperature and pressure, where the pressure changes occurring especially from altitude changes. During use, a drive signal, such as a pulse train, moves the galvanometer or oscillator at or near its resonant frequency. Based on a parameter of the drive signal, such as pulse width, the ambient pressure can be made known. In general, a high-pressure environment requires a relatively longer pulse width to resonate the galvanometer or oscillator in comparison to a shorter pulse width for a low-pressure environment. Corrections to print quality stem from the determined ambient pressure.

Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to temperature. A moving galvanometer or oscillator reflects a laser beam to create forward and reverse scan lines of a latent image. During use, the actual ambient temperature is obtained and used make corrections to improve print quality, such as by producing the latent image with a signal altered from an image data input signal to help ensure proper alignment of the forward and reverse scan lines.

Abstract: In a bi-directionally scanning electrophotographic (EP) device, methods and apparatus include storing alignment information. In one aspect, pre-characterization parameters of the EP device are stored in memory, such as NVRAM, resistant to the removal of power. In another, actual parameters of the EP device are learned during calibration and stored in the same memory. A controller has local or remote access to the memory and makes comparisons of the pre-characterized and learned parameters to implement corrections. Especially, scan alignment corrections are implemented to alter future scanning of scan lines of latent images on a photoconductor whereby the scan lines are formed in alternating directions. Certain contemplated parameters include, but are not limited to, a scan detect to print distance from a sensor to the start of imaging, temperature, pressure, a scanning mechanism drive signal parameter, such as pulse width, or sensor delay information.

Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to ambient pressure in which operated. A moving galvanometer or oscillator reflects a laser beam to create scan lines of a latent image in opposite directions. A damping of the motion occurs per air density implicated by temperature and pressure, where the pressure changes occurring especially from altitude changes. During use, a drive signal, such as a pulse train, moves the galvanometer or oscillator at or near its resonant frequency. Based on a parameter of the drive signal, such as pulse width, the ambient pressure can be made known. In general, a high-pressure environment requires a relatively longer pulse width to resonate the galvanometer or oscillator in comparison to a shorter pulse width for a low-pressure environment. Corrections to print quality stem from the determined ambient pressure.

Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to temperature. A moving galvanometer or oscillator reflects a laser beam to create forward and reverse scan lines of a latent image. During use, the actual ambient temperature is obtained and used make corrections to improve print quality, such as by producing the latent image with a signal altered from an image data input signal to help ensure proper alignment of the forward and reverse scan lines.

Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to ambient pressure in which operated. A moving galvanometer or oscillator reflects a laser beam to create scan lines of a latent image in opposite directions. A damping of the motion occurs per air density implicated by temperature and pressure, where the pressure changes occurring especially from altitude changes. During use, a drive signal, such as a pulse train, moves the galvanometer or oscillator at or near its resonant frequency. Based on a parameter of the drive signal, such as pulse width, the ambient pressure can be made known. In general, a high-pressure environment requires a relatively longer pulse width to resonate the galvanometer or oscillator in comparison to a shorter pulse width for a low-pressure environment. Corrections to print quality stem from the determined ambient pressure.

Abstract: In a bi-directionally scanning electrophotographic (EP) device, methods and apparatus include storing alignment information. In one aspect, pre-characterization parameters of the EP device are stored in memory, such as NVRAM, resistant to the removal of power. In another, actual parameters of the EP device are learned during calibration and stored in the same memory. A controller has local or remote access to the memory and makes comparisons of the pre-characterized and learned parameters to implement corrections. Especially, scan alignment corrections are implemented to alter future scanning of scan lines of latent images on a photoconductor whereby the scan lines are formed in alternating directions. Certain contemplated parameters include, but are not limited to, a scan detect to print distance from a sensor to the start of imaging, temperature, pressure, a scanning mechanism drive signal parameter, such as pulse width, or sensor delay information.

Abstract: Methods and apparatus include improving print quality of a bi-directionally scanning electrophotographic (EP) device, such as a laser printer or copy machine, according to either or both of ambient pressure and temperature in which operated. A moving galvanometer or oscillator reflects a laser beam to create scan lines of a latent image in opposite directions. A damping of the motion of the galvanometer or oscillator occurs per the pressure and temperature and is, thus, characterized. During use, the actual ambient pressure and temperature are obtained and correlated to the characterization. Corrections to improve print quality then occur according to the characterization. Certain corrections include producing the latent image with a signal altered from an image data input signal. Delaying contemplates fractions of pixels and whether a left or right half or a forward or reverse scan line of the image is under consideration.

Abstract: An improved method and apparatus for controlling a scanning laser are provided by the present invention. In accordance with a preferred embodiment, a single feedback sensor is placed along the scan path of a scanning laser such that it senses the laser twice during each scan. The time intervals between the sensor sensing the laser are measured and examined to determine the position and direction of the scanning laser. These time intervals may also be used to ensure that the scanning device is operating at its resonant frequency. In systems that require detecting the laser as it enters and leaves the imaging window, a reflective device is used to create a beam path from the edge of the imaging window back to the single feedback sensor such that the sensor detects the laser four times during each scan.

Abstract: An imaging system in which a modulated light beam is reflected by a reflection surface oscillated by a torsion oscillator, such imaging system being capable of operating dynamically to adjust to the change in resonant frequency of the torsion oscillator. The resonant frequency of the torsion oscillator varies with ambient temperature and with other factors, such as amount of use. Sensors sense the sweep of the light beam to determine a currently existing resonant frequency of the torsion oscillator. The rate of modulation of the beam by a laser is adjusted to conform the modulation in the sweep direction to the desired resolution of the image. Similarly, the speed of movement of a surface being imaged is adjusted to conform the modulation to the desired resolution in the direction perpendicular to the sweep direction. Optionally, the electrical drive frequency of the torsion oscillator may also be adjusted to correspond with the currently existing resonant frequency during physical operation.

Abstract: A method and device for managing and controlling a scanning system that incorporates multiple oscillating scanners is provided by the present invention. In accordance with the preferred embodiment, a resonant frequency is determined for each of the scanners. A drive signal for driving the oscillating scanners is generated based upon the determined resonant frequencies. An amplitude adjustment circuit determines the difference between the drive signal frequency and the resonant frequency of each oscillating scanner and adjusts the amplitude of the drive signal provided to that particular oscillating scanner such that scan amplitude of each oscillating scanner is approximately equal. The offset from the resonant frequency is also used to calculate a phase adjustment for the drive signal to insure that the oscillating scanners are operating in tandem.

Abstract: In bi-directional imaging, such as bi-directional printing, a galvanometric oscillator scans a light beam through a scan path across an imaging window. A controller enables transmission of video data to a modulator when the light beam is positioned for imaging on the imaging window. Video data is transmitted to the modulator when the light beam is traveling in a forward direction or a reverse direction across the imaging window, whereby a modulated light beam is capable of producing an image when traveling in the forward or reverse directions.

Abstract: An imaging system in which a modulated light beam is reflected by a reflection surface oscillated by a torsion oscillator, such imaging system being capable of operating dynamically to adjust to the change in resonant frequency of the torsion oscillator. The resonant frequency of the torsion oscillator varies with ambient temperature and with other factors, such as amount of use. Sensors sense the sweep of the light beam to determine a currently existing resonant frequency of the torsion oscillator. The rate of modulation of the beam by a laser is adjusted to conform the modulation in the sweep direction to the desired resolution of the image. Similarly, the speed of movement of a surface being imaged is adjusted to conform the modulation to the desired resolution in the direction perpendicular to the sweep direction. Optionally, the electrical drive frequency of the torsion oscillator may also be adjusted to correspond with the currently existing resonant frequency during physical operation.

Abstract: An improved method and apparatus for controlling a scanning laser are provided by the present invention. In accordance with a preferred embodiment, a single feedback sensor is placed along the scan path of a scanning laser such that it senses the laser twice during each scan. The time intervals between the sensor sensing the laser are measured and examined to determine the position and direction of the scanning laser. These time intervals may also be used to ensure that the scanning device is operating at its resonant frequency. In systems that require detecting the laser as it enters and leaves the imaging window, a reflective device is used to create a beam path from the edge of the imaging window back to the single feedback sensor such that the sensor detects the laser four times during each scan.

Abstract: A method and device for managing and controlling a scanning system that incorporates multiple oscillating scanners is provided by the present invention. In accordance with the preferred embodiment, a resonant frequency is determined for each of the scanners. A drive signal for driving the oscillating scanners is generated based upon the determined resonant frequencies. An amplitude adjustment circuit determines the difference between the drive signal frequency and the resonant frequency of each oscillating scanner and adjusts the amplitude of the drive signal provided to that particular oscillating scanner such that scan amplitude of each oscillating scanner is approximately equal. The offset from the resonant frequency is also used to calculate a phase adjustment for the drive signal to insure that the oscillating scanners are operating in tandem.

Abstract: In bi-directional imaging, such as bi-directional printing, a galvanometric oscillator scans a light beam through a scan path across an imaging window. A controller enables transmission of video data to a modulator when the light beam is positioned for imaging on the imaging window. Video data is transmitted to the modulator when the light beam is traveling in a forward direction or a reverse direction across the imaging window, whereby a modulated light beam is capable of producing an image when traveling in the forward or reverse directions.

Abstract: Printer (1) receives revised operating code in flash memory (19). To preserve offset adjustment unique to the printer, the values in new operating code are compared with those in the previous code, and new offsets preserving the previous offsets are stored in permanent memory (21). The use of permanent memory is minimized by basing the calculation on changes from start of production.